<?xml version="1.0" encoding="UTF-8"?>

   <schema targetNamespace="urn:ietf:params:xml:ns:ipfix-info"
           xmlns:ipfix="urn:ietf:params:xml:ns:ipfix-info"
           xmlns="http://www.w3.org/2001/XMLSchema"
           elementFormDefault="qualified">

     <simpleType name="dataType">
       <restriction base="string">
         <enumeration value="unsigned8">
           <annotation>
             <documentation>The type "unsigned8" represents a
               non-negative integer value in the range of 0 to 255.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="unsigned16">
           <annotation>
             <documentation>The type "unsigned16" represents a
               non-negative integer value in the range of 0 to 65535.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="unsigned32">
           <annotation>
             <documentation>The type "unsigned32" represents a
                non-negative integer value in the range of 0 to
                4294967295.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="unsigned64">
           <annotation>
             <documentation>The type "unsigned64" represents a
               non-negative integer value in the range of 0 to
               18446744073709551615.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed8">
           <annotation>
             <documentation>The type "signed8" represents
               an integer value in the range of -128 to 127.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed16">
           <annotation>
             <documentation>The type "signed16" represents an
               integer value in the range of -32768 to 32767.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed32">
           <annotation>
             <documentation>The type "signed32" represents an
                integer value in the range of -2147483648 to
                2147483647.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed64">
           <annotation>
             <documentation>The type "signed64" represents an
                integer value in the range of -9223372036854775808
                to 9223372036854775807.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="float32">
           <annotation>
             <documentation>The type "float32" corresponds to an IEEE
               single-precision 32-bit floating point type as defined
               in [IEEE.754.1985].
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="float64">
           <annotation>
             <documentation>The type "float64" corresponds to an IEEE
               double-precision 64-bit floating point type as defined
               in [IEEE.754.1985].
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="boolean">
           <annotation>
             <documentation>The type "boolean" represents a binary
               value.  The only allowed values are "true" and "false".
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="macAddress">
           <annotation>
             <documentation>The type "macAddress" represents a
               string of 6 octets.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="octetArray">
           <annotation>
             <documentation>The type "octetArray" represents a finite
             length string of octets.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="string">
           <annotation>
             <documentation>
               The type "string" represents a finite length string
               of valid characters from the Unicode character encoding
               set [ISO.10646-1.1993].  Unicode allows for ASCII
               [ISO.646.1991] and many other international character
               sets to be used.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeSeconds">
           <annotation>
             <documentation>
               The type "dateTimeSeconds" represents a time value
               in units of seconds normalized to the
               GMT time zone.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeMilliseconds">
           <annotation>
             <documentation>The type "dateTimeMilliseconds" represents
               a time value in units of milliseconds
               normalized to the GMT time zone.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeMicroseconds">
           <annotation>
             <documentation>The type "dateTimeMicroseconds" represents
               a time value in units of microseconds
               normalized to the GMT time zone.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeNanoseconds">
           <annotation>
             <documentation>The type "dateTimeNanoseconds" represents
               a time value in units of nanoseconds
               normalized to the GMT time zone.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="ipv4Address">
           <annotation>
             <documentation>The type "ipv4Address" represents a value
               of an IPv4 address.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="ipv6Address">
           <annotation>
             <documentation>The type "ipv6Address" represents a value
               of an IPv6 address.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <simpleType name="dataTypeSemantics">
       <restriction base="string">
         <enumeration value="quantity">
           <annotation>
             <documentation>
               A quantity value represents a discrete
               measured value pertaining to the record. This is
               distinguished from counters which represent an ongoing
               measured value whose "odometer" reading is captured as
               part of a given record. If no semantic qualifier is
               given, the Information Elements that have an integral
               data type should behave as a quantity.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="totalCounter">
           <annotation>
             <documentation>
               An integral value reporting the value of a counter.
               Counters are unsigned and wrap back to zero after
               reaching the limit of the type. For example, an
               unsigned64 with counter semantics will continue to
               increment until reaching the value of 2**64 - 1.  At
               this point the next increment will wrap its value to
               zero and continue counting from zero.  The semantics
               of a total counter is similar to the semantics of
               counters used in SNMP, such as Counter32 defined in
               RFC 2578 [RFC2578].  The only difference between total
               counters and counters used in SNMP is that the total
               counters have an initial value of 0.  A total counter
               counts independently of the export of its value.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="deltaCounter">
           <annotation>
             <documentation>
               An integral value reporting the value of a counter.
               Counters are unsigned and wrap back to zero after
               reaching the limit of the type. For example, an
               unsigned64 with counter semantics will continue to
               increment until reaching the value of 2**64 - 1.  At
               this point the next increment will wrap its value to
               zero and continue counting from zero.  The semantics
               of a delta counter is similar to the semantics of
               counters used in SNMP, such as Counter32 defined in
               RFC 2578 [RFC2578].  The only difference between delta
               counters and counters used in SNMP is that the delta
               counters have an initial value of 0.  A delta counter
               is reset to 0 each time its value is exported.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="identifier">
           <annotation>
             <documentation>
               An integral value which serves as an identifier.
               Specifically mathematical operations on two
               identifiers (aside from the equality operation) are
               meaningless. For example, Autonomous System ID 1 *
               Autonomous System ID 2 is meaningless.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="flags">
           <annotation>
             <documentation>
               An integral value which actually represents a set of
               bit fields.  Logical operations are appropriate on
               such values, but not other mathematical operations.
               Flags should always be of an unsigned type.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <simpleType name="applicability">
       <restriction base="string">
         <enumeration value="data">
           <annotation>
             <documentation>
               Used for Information Elements that are applicable to
               Flow Records only.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="option">
           <annotation>
             <documentation>
               Used for Information Elements that are applicable to
               option records only.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="all">
           <annotation>
             <documentation>
               Used for Information Elements that are applicable to
               Flow Records as well as to option records.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <simpleType name="status">
       <restriction base="string">
         <enumeration value="current">
           <annotation>
             <documentation>
               Indicates that the Information Element definition
               is that the definition is current and valid.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="deprecated">
           <annotation>
             <documentation>
               Indicates that the Information Element definition is
               obsolete, but it permits new/continued implementation
               in order to foster interoperability with older/existing
               implementations.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="obsolete">
           <annotation>
             <documentation>
               Indicates that the Information Element definition is
               obsolete and should not be implemented and/or can be
               removed if previously implemented.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <complexType name="text">
       <choice maxOccurs="unbounded" minOccurs="0">
         <element name="paragraph">
           <complexType mixed="true">
             <sequence>
                <element maxOccurs="unbounded" minOccurs="0"
                  name="xref">
                  <complexType>
                    <attribute name="target" type="string"
                      use="required"/>
                  </complexType>
                </element>
             </sequence>
           </complexType>
         </element>
         <element name="artwork">
           <simpleType>
             <restriction base="string"/>
           </simpleType>
         </element>
       </choice>
     </complexType>

     <simpleType name="range">
       <restriction base="string"/>
     </simpleType>

     <element name="fieldDefinitions">
       <complexType>
         <sequence>
           <element maxOccurs="unbounded" minOccurs="1" name="field">
             <complexType>
               <sequence>
                 <element maxOccurs="1" minOccurs="1" name="description"
                          type="ipfix:text">
                   <annotation>
                     <documentation>
                       The semantics of this Information Element.
                       Describes how this Information Element is
                       derived from the Flow or other information
                       available to the observer.
                     </documentation>
                   </annotation>
                 </element>

                 <element maxOccurs="1" minOccurs="0" name="reference"
                          type="ipfix:text">
                   <annotation>
                     <documentation>
                       Identifies additional specifications which more
                       precisely define this item or provide additional
                       context for its use.
                     </documentation>
                   </annotation>
                 </element>

                 <element maxOccurs="1" minOccurs="0" name="units"
                          type="string">
                   <annotation>
                     <documentation>
                       If the Information Element is a measure of some
                       kind, the units identify what the measure is.
                     </documentation>
                   </annotation>
                 </element>

                 <element maxOccurs="1" minOccurs="0" name="range"
                          type="ipfix:range">
                   <annotation>
                     <documentation>
                       Some Information Elements may only be able to
                       take on a restricted set of values which can be
                       expressed as a range (e.g. 0 through 511
                       inclusive). If this is the case, the valid
                       inclusive range should be specified.
                     </documentation>
                   </annotation>
                 </element>
               </sequence>

               <attribute name="name" type="string" use="required">
                 <annotation>
                   <documentation>
                     A unique and meaningful name for the Information
                     Element.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="dataType" type="ipfix:dataType"
                          use="required">
                 <annotation>
                   <documentation>
                     One of the types listed in section 3.1 of this
                     document or in a future extension of the
                     information model. The type space for attributes
                     is constrained to facilitate implementation.  The
                     existing type space does however encompass most
                     basic types used in modern programming languages,
                     as well as some derived types (such as ipv4Address)
                     which are common to this domain and useful
                     to distinguish.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="dataTypeSemantics"
                          type="ipfix:dataTypeSemantics" use="optional">
                 <annotation>
                   <documentation>
                     The integral types may be qualified by additional
                     semantic details. Valid values for the data type
                     semantics are specified in section 3.2 of this
                     document or in a future extension of the
                     information model.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="elementId" type="nonNegativeInteger"
                          use="required">
                 <annotation>
                   <documentation>
                     A numeric identifier of the Information Element.
                     If this identifier is used without an enterprise
                     identifier (see [I-D.ietf-ipfix-protocol] and
                     enterpriseId below), then it is globally unique
                     and the list of allowed values is administered by
                     IANA.  It is used for compact identification of an
                     Information Element when encoding Templates in the
                     protocol.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="enterpriseId" type="nonNegativeInteger"
                          use="optional">
                 <annotation>
                   <documentation>
                     Enterprises may wish to define Information Elements
                     without registering them with IANA, for example for
                     enterprise-internal purposes. For such Information
                     Elements the Information Element identifier
                     described above is not sufficient when the
                     Information Element is used outside the enterprise.
                     If specifications of enterprise-specific
                     Information Elements are made public and/or if
                     enterprise-specific identifiers are used by the
                     IPFIX protocol outside the enterprise, then the
                     enterprise-specific identifier MUST be made
                     globally unique by combining it with an enterprise
                     identifier.  Valid values for the enterpriseId are
                     defined by IANA as SMI network management private
                     enterprise codes.  They are defined at
                     http://www.iana.org/assignments/enterprise-numbers.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="applicability"
                          type="ipfix:applicability" use="optional">
                 <annotation>
                   <documentation>This propoerty of an Information
                   Element indicates in which kind of records the
                   Information Element can be used.
                   Allowed values for this property are 'data',
                   'option', and 'all'.</documentation>
                 </annotation>
               </attribute>

               <attribute name="status" type="ipfix:status"
                          use="required">
                 <annotation>
                   <documentation>
                     The status of the specification of this
                     Information Element.  Allowed values are 'current',
                     'deprecated', and 'obsolete'.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="group" type="string"
                          use="required">
                 <annotation>
                   <documentation>to be done ...</documentation>
                 </annotation>
               </attribute>

             </complexType>
           </element>
         </sequence>
       </complexType>

       <unique name="infoElementIdUnique">
         <selector xpath="field"/>

         <field xpath="elementId"/>
       </unique>
     </element>
   </schema>
